Objectively in the sense that there are actual causes in you life that distress you and cause your symptoms instead of thinking your life is shitty because you are depressed. Of course being able to determine if it is your depression talking or if things are objectively bad isn't easy and people often need outside help from a therapist for that. Plus it isn't really clear cut in practice.

On a sidenote, I know that knowing that it is "just your depression talking" is also a pretty hard pill to swallow and not always helpful. Personally I have a lot of fears that I know are irrational but that doesn't make them any less real.

And even if your problems are external, sometimes you need to focus and your inner self first, find some strength and help so you can tackle the external problems later. But for other people "working on yourself" can be avoiding the actual problems they need to work on.

And yes happiness is always relative.